4GB vs 2GB RAM?

On the new MB, will a see a noticeable difference between having 2gb and 4gb RAM? I'm taking the plunge and installing RAM from Crucial for the first time so it's only about £120 for 4gb, rather than £464 (edu) when direct! I'm not a 'heavy' user - web, Office, iPhoto, iTunes and the odd game here and there, (FM2008 at the moment,) is what i'll be doing.

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